The amount of force output required by a steering system is proportional to the lateral load on the front axle. At speed, the lateral load is generated primarily by the lateral acceleration of the vehicle. The force output of the power steering system is generated by the assist pressure and force input by the driver. The type of steering maneuver a vehicle is performing can be determined by observing the assist pressure, its change with time, and the vehicle speed. With this information a variable assist power steering system can provide the optimum input force to output force relationship for a given steering maneuver. Unfortunately, conventional variable assist power steering systems use only vehicle speed as an input to the electronic control module and the input to output force relationships remain constant for a give n vehicle speed. Consequently, these relationships are a compromise and may not be ideal for any one condition. Accordingly, it will be appreciated that it would be highly desirable to have a power steering system that uses more than vehicle speed as an input to the electronic control module so the input force to output force relationships more accurately reflect driving conditions.